1. Field of the Invention
The present invention relates to document display apparatuses and document display programs and, more particularly, to a document display apparatus and a document display program that facilitate a user viewing contents of documents.
2. Description of the Related Art
In the present office environment, with a background of reducing papers, saving spaces and sharing information, paper documents have been managed by making electronic document data via reading documents using a reading device such as a scanner or the like. In order to review this—created document data, software for reviewing document data (referred to as a document data viewer) is installed in a personal computer (PC) serving as a user terminal.
A description will be given below of how software for viewing document data (the document data viewer) provides a document data reviewing function to a user. First, as a process prior to viewing, document elements constituting a document, such as “character elements”, “drawing elements”, “table elements”, “image elements”, “ruled line elements”, etc., are extracted by using an area discrimination technique in a case of image type document data or by directly discriminating data codes in a case of individual application data type document data, and the extracted document elements are displayed on a display screen.
In such software for viewing document data (document data viewer), functions which users ask for are operationality to enable a user to easily view the document data which the user wants to view and with respect to the contents of document data being easily read visually. However, there are various environments in which users view document data. There are considered mobile terminals such as a cellular phone or a personal digital assistant (PDA) other than personal computers (PCs). Accordingly, an optimum environment for viewing document data is not always put in place.
Thus, a problem arises in document data viewing software (document data viewer) is how to acquire operationality or visibility corresponding to a display environment of a user. For example, there is suggested a technique to acquire visibility by controlling an amount of information to be displayed in accordance with a size or a resolution, which are the display environment of a user (see Japanese Laid-Open Patent Application No. 8-153100). Additionally, there is suggested a technique to acquire operationality and visibility by displaying an index of a tree structure having a development/folding function based on a hierarchical structure of a document and selecting an item to be viewed from the index. See also Japanese Laid-Open Patent Application No. 2001-297303
Moreover, generally, the document data viewing software (document viewer) has a function to allow a user to arbitrarily select a display method to meet for the purpose of viewing. For example, there is a function to reduce a size of an entire document image in response to a page size in consideration of a case where a user wants to grasp the entire document. There also is a function to enlarge a document image in response to a page width in consideration of a case where a user wants to view the contents of the document in detail. Further, there is a function to enlarge a part of a document image at an arbitrary magnification, like a magnifying glass, by pointing a pointer of a pointing device to a part which the user wants to view.
As mentioned above, the document data viewing software (document data viewer) provides operationality and visibility when a user views document data.
However, when a user attempts to display contents, which the user wants to view, by using an enlarging function provided to the conventional document data viewing software, only a part of the contents may be displayed due to a magnification to the size of the display screen. In order to display the rest of the contents, the user must move a scroll bar provided in the display window upward and downward and leftward and rightward to move the part of the contents into a display range of the display window. Such an operation is inconvenient for the user, and it cannot be the that operationality and visibility are provided.